At present, rapid development of new technologies such as wearable computing technology, mobile computing technology, pervasive computing technology or the like poses a new challenge and a higher requirement on a human-computer interaction technology, while providing many new opportunities. At this stage, there has been some development regarding natural and harmonious human-computer interaction modes, the main characteristic thereof being a single-channel or multiple-channel interaction by an input method based on a gesture, an expression, voice, a handwritten form or the like, and the purpose thereof is to conduct human-computer interaction operation by motion, voice, expression and in other natural manners, which is the “user freedom” as emphasized in ideal human-computer interaction.